• inverse pneumatic artificial muscles
• mechanical instability
• soft actuation system
• soft artificial ventricle

Cardiovascular diseases (CVDs) are the leading cause of death globally. The transplant is often the only solution, so donors' limited availability and compatibility represent the greatest obstacle. These considerations led to the development of new cardiac devices to substitute the missed human cardiac functionalities, such as Total Artificial Heart (TAH). Currently, available TAHs are characterized by rigid components. High complication rates, bulkiness, short durability, poor biocompatibility, and low patient quality of life are some of the key drawbacks of existing TAHs. Soft materials provide a potential solution for the aforementioned problems. They can be used to create a device that can mimic the physiological motions of a real human heart and be suitable for safe interaction with humans with fewer biocompatibility troubles and adverse effects than the current devices. The aim of this thesis is the design, fabrication, and characterization of a soft actuation system for an artificial heart ventricle. Soft Inverse Pneumatic Artificial Muscles (IPAM) are designed, fabricated, and characterized to obtain highly-performant and reliable actuators, through the use of a bellows braid. To enhance the artificial ventricle’s performance and reach physiologically relevant conditions, the mechanical instability of the soft ventricle chamber is studied and harnessed as an amplifying tool. This instability study is based on experimental tests to induce folding behaviours in the soft chamber by applying external axial and rotational forces. Successively, analytical models are developed with the aim of understanding the mechanical coupling between the highly non-linear chamber and the IPAMs. Finally, the entire ventricle is assembled and tested under quasi-static and dynamic conditions, through a Mock Circulation Loop. Despite its early stage of development, the proposed device succeeds in giving rational design rules, partially filling the gap between soft robotic simulators and implantable devices for assistance and organ replacement.